What happened
During a local flight, the crew observed oil accumulating on the windscreen accompanied by significant vibrations throughout the airplane. The pilots decided to return to the departure airport; however, the aircraft approached the runway at an excessive speed and altitude.
In an attempt to execute a go-around, the pilot applied full throttle, but this resulted in very high vibration and minimal additional power. While performing a left turn during the maneuver, the engine lost power completely. The crew subsequently performed a forced landing, during which the aircraft impacted trees and shrubs.
The investigation
An examination of the engine revealed that the insulation on the 'P' leads for both magnetos had deteriorated. This condition caused the magnetos to ground out intermittently. An FAA Inspector noted that these 'P' leads were likely the original equipment from when the aircraft was manufactured in 1959. The inspector concluded that this deterioration could have caused the magnetos to ground, leading to the loss of engine power.
Records indicated that the most recent annual inspection of the aircraft had been completed approximately 14 months prior to the accident. Additionally, it was determined that the pilot did not possess a current medical certificate or a biennial flight review.